Direct from Wikileaks staffers:
"Why do you only seem to have information on Democrats?
If you were as Noble as you say you would believe in government accountability at all levels, not just for one party."
"To date, we have not received information on Donald Trump’s campaign, or other campaigns. If it were to be submitted now we would happily publish it. Information on how campaigns are fought is important in the moment, and after to learn lessons from. We certainly believe in accountability and transparency for the powerful. And this includes for all the campaigns in the election. We can of course only publish what we receive. If anyone has information on any of the other campaigns we urge them to submit it now before it is deleted -
https://wikileaks.org/#submit"
Wikileaks obtains leaks through anonymous submissions only, they then check for verification and then release when they deem them most effective in generating awareness.